1. (The Field of the Invention)
The present invention relates to an endoscope system equipped with an endoscope to which various medical instruments can be attached detachably for use, and in particular, to the endoscope system that improves the operationality of the medical instruments.
2. (Related Art)
Recently, endoscopes have been used widely in the medical field as well as the industrial field. In general, each of these endoscopes is equipped with a thin and elongated insertion tube and an operation unit equipped with various operating members such as knobs and switches for commanding various functions of the endoscope. The insertion tube has a flexibly bendable section located at a distal portion thereof.
In using an industrial endoscope, the insertion tube is Inserted into boilers, gas turbine engines, pipes in chemical plants, bodies of automobile engines, and others, so that portions to be examined can be observed for scratches, cracks, corrosion, and other doubtful damages, and can be tested according to need.
Further, in using a medical endoscope, the insertion tube is Inserted to a body cavity of an object being examined, so that internal organs in the body cavity can be observed and therapeutic instruments Inserted through a therapeutic channel of the endoscope can be used for various types of therapy, if needed.
Especially, in using the conventional medical endoscope, an operator manually inserts a therapeutic instrument into the therapeutic channel with the sheath of the therapeutic instrument held by the operator. In this case, the therapeutic instrument has a length of some 2 m, whereby it takes much time to insert the therapeutic instrument. In addition, the inserting operation must be done with attention. Thus the insertion becomes a troublesome operation for the operator, making operating various therapeutic instruments difficult.
To overcome such difficulties, Japanese Patent Laid-open Publication No. 57-190541 discloses an endoscope that is able to cope with delicate manual inserting operations. That is, the endoscope is provided with a conveying unit for mechanically inserting and pulling a therapeutic instrument into the therapeutic channel of the endoscope. The conveying unit is constructed such that when the therapeutic instrument reaches a position near to the distal portion of the insertion element, the mechanical insertion is released so as to allow the delicate manual inserting operations.
Further, Japanese Patent Laid-open Publication No. 2000-000207 discloses a conveying unit for therapeutic instruments used in combination with an endoscope. In this disclosure, in addition to a configuration that allows therapeutic instruments to be inserted in or pulled out from the therapeutic channel, the conveying unit is equipped with actuating means for actuating a therapeutic member arranged at the tip of each therapeutic instrument and foot switches used to command various inserting and pulling-out operations of the conveying unit.
In operations for a therapeutic instrument, a therapeutic instrument is guided smoothly into the therapeutic channel of an endoscope with the flexibly bendable section bended or is made to smoothly pass the bended bendable section so as to come from the distal portion. In such situations, the larger a curbed angle of the bendable section becomes, the larger the power required for inserting and pulling out the therapeutic instrument. However, the configurations shown by the foregoing two patent publications have a difficulty in a case where the power is set to a value necessary for smooth inserting and pulling-out operations of a therapeutic instrument into and from the bendable section bent at a maximum curve angle thereof. In this case, the bendable section is in a straight (no curved) or in a less curved angle state, the therapeutic instrument is forced to be inserted and pulled out by power larger than an optimally necessary amount, thus making desired inserting and pulling-out operations difficult.
The type of endoscope to be used depends on types of surgeries and different types of endoscopes have therapeutic channels of which diameters are also different from each other. Thus, when the bendable section of an endoscope is bent, a small amount of play between the wall of the therapeutic channel and the sheath of the therapeutic instrument may cause a delay in the response of the inserting and pulling-out operations of the therapeutic instrument.
Additionally, in the case of the configuration shown by the later patent publication, when the bendable section is bent, the similar difficulty to the inserting and pulling-out operations may be caused in a force to open and close such therapeutic instruments as clamping forceps as well as an amount to be open and closed thereof.